Relooking at your timings and mine, it appears that you allocate 10x my count
of register-size count of items and require 10x the FillChar which you need to
initialize your filter array.
My timing is about 80 ms and yours looks like 900 ms for 10x more register
sized data, which look like the r
2014-11-04 6:35 GMT+08:00 Nico Erfurth :
>
> Well, the first thing you should ask yourself is "Do I REALLY need such
> a large bloom filter". Everything larger than the last level cache will
> seriously harm your performance as you are going to trigger a lot of
> cache and TLB misses. In general y
Hi,
> Hi All,
>
> I am programming a Bloom Filter and need a high-performance way to
>
> On what platform are you doing this ?
>
> I am programming on Linux, but it will be used on both Windows and
> Linux, Windows is the primary target.
Well, the first thing you should
2014-11-03 23:40 GMT+08:00 Adriaan van Os :
> Xiangrong Fang wrote:
>
>> Hi All,
>>
>> I am programming a Bloom Filter and need a high-performance way to
>>
>
> On what platform are you doing this ?
>
I am programming on Linux, but it will be used on both Windows and Linux,
Windows is the primar
Xiangrong Fang wrote:
Hi All,
I am programming a Bloom Filter and need a high-performance way to
On what platform are you doing this ?
Regards,
Adriaan van Os
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Am 03.11.2014 08:32 schrieb "Nico Erfurth" :
>
> On 02.11.14 15:05, Xiangrong Fang wrote:
> > Sorry, the results in previous mail was mis-labeled.
> >
> >
> > The result is:
> >
> > Using SetLength:
> >
> > Alloc: 9.40781697E-0001
> > Clear: 2.13420202E-0001
> >
> > Using GetMem
My results :
_Ptr:=GetMem(1)18 mus, 824 ns / GetMem
_Ptr:=GetMem(1) + FillChar(_Ptr^,1,0)); 81 ms / GetMem +
FillChar
var
ArInt:array of int32;
.
SetLength(ArInt, 1 shr 2); 81 ms / SetLength
All timings are variable within [time, time+8%] on rep
2014-11-03 14:39 GMT+08:00 Sven Barth :
>
> Would you mind to show the timings that you got for FillChar? :)
Using FillChar is always about 5% (or less) faster than FillQWord when
used with GetMemory, but will be around 20%-40% faster if the memory is
allocated by SetLength.
Additionally this
On 02.11.14 15:05, Xiangrong Fang wrote:
> Sorry, the results in previous mail was mis-labeled.
>
>
> The result is:
>
> Using SetLength:
>
> Alloc: 9.40781697E-0001
> Clear: 2.13420202E-0001
>
> Using GetMemory:
>
> Alloc: 2.8100E-0005
> Clear: 7.74975500
On 11/02/2014 03:54 PM, Xiangrong Fang wrote:
Hi All,
...
Also, I usually use pointer to pass block of memory to functions. How
do I implement a function with the following signature:
procedure MyProc(var Buf; Len: Integer):
I mean, how to handle "var Buf" inside the procedure body?
You c
On 03.11.2014 02:59, Xiangrong Fang wrote:
2014-11-03 2:50 GMT+08:00 Sven Barth mailto:pascaldra...@googlemail.com>>:
If you use SetLength the dynamic array consists not only of the
array data, but also of an information record in front of it. This
will likely lead to the data not be
2014-11-03 2:50 GMT+08:00 Sven Barth :
> If you use SetLength the dynamic array consists not only of the array
> data, but also of an information record in front of it. This will likely
> lead to the data not being aligned correctly (FillQWord works best with
> 8-Byte alignment). So what about tes
On Sun, Nov 2, 2014 at 3:54 PM, Xiangrong Fang wrote:
> Also, I usually use pointer to pass block of memory to functions. How do
> I implement a function with the following signature:
>
> procedure MyProc(var Buf; Len: Integer):
>
> I mean, how to handle "var Buf" inside the procedure body?
>
U
Am 02.11.2014 14:55 schrieb "Xiangrong Fang" :
>
> Hi All,
>
> I am programming a Bloom Filter and need a high-performance way to
allocate and wipe large block of memory. I did the following test:
>
> program getmem;
> {$mode objfpc}{$H+}
> uses epiktimer;
> const
> SIZE = 1024 * 1024 * 1024;
>
Sorry, the results in previous mail was mis-labeled.
The result is:
Using SetLength:
Alloc: 9.40781697E-0001
Clear: 2.13420202E-0001
Using GetMemory:
Alloc: 2.8100E-0005
Clear: 7.74975504E-0001
___
fpc-pascal
Hi All,
I am programming a Bloom Filter and need a high-performance way to allocate
and wipe large block of memory. I did the following test:
program getmem;
{$mode objfpc}{$H+}
uses epiktimer;
const
SIZE = 1024 * 1024 * 1024;
CNT = 10;
var
a: array of Byte;
p: Pointer;
et: TEpikTimer;
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